<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <h1>form</h1>
    <hr>

    <form action="1.php" name="myform" id="ff">
        username: <input type="text" name="username" value="laowangba">

        <button type="submit">submit</button>
    </form>

    <hr>
    <br>

    <button form="ff">HTML5 按钮</button>
    <button onclick="document.myform.submit()">JS (submit)</button>

    <button onclick="document.myform.reset()">JS (reset)</button>
</body>
</html>